Trident, Athena launch complex. This complex was built as part of the U.S. Navy's Trident II ballistic missile effort at the Cape. Construction was underway in February 1984, and the complex was ordnance-certified in November 1986. Complex 46 supported the Cape's first Trident II test missile launch on 15 January 1987. Eighteen more Trident IIs were launched from the site between 17 March 1987 and 27 January 1989. As Trident launch operations moved out to sea later in 1989, the complex was placed on standby status awaiting special Trident II test requirements. No new requirements surfaced in the 1990s, but the Spaceport Florida Authority (SFA) won $4,890,000 in Air Force grants to redesign Complex 46 to handle small commercial space launch operations (e.g., Lockheed Martin's new LMLV-2 space launch vehicle).

A Critical Design Review (CDR) for the complex was held in March 1996, and construction was underway shortly thereafter. Modifications included a new launch mount, a Mobile Access Structure (MAS), an umbilical foundation and service trenches and conduits. Spaceport Florida opened Complex 46 for commercial space launch operations on 29 May 1997. The complex supported its first commercial space launch - an Athena II carrying the Lunar Prospector spacecraft - on 7 January 1998.

The Lunar Prospector was designed for a low polar orbit investigation of the Moon, including mapping of surface composition and possible polar ice deposits, measurements of magnetic and gravity fields, and study of lunar outgassing events. Data from the 1 to 3 year mission will allow construction of a detailed map of the surface composition of the Moon, and will improve understanding of the origin, evolution, current state, and resources of the Moon. After launch, the Lunar Prospector had a 105 hour cruise to the Moon, followed by insertion into a near-circular 100 km altitude lunar polar orbit with a period of 118 minutes. The nominal mission duration was one year.